What does it mean, when a software has been “leaked”?
Leak. In software engineering, when we say a software has “leaked” it means:
1. The software is under development (DEV)…
2. An important information from the software has been sold out.
The software is under development (DEV) and has been “Leaked”.
In Computer Science, “Dev” is the short form for “Development” or “Developer”. When we say a software is under Development and has been leaked it means it hasn’t been fully completed. It can contain errors (not virus) when using it. We call it “bugs”. Many software development companies such as Microsoft distribute a software which is under development to their programmers ONLY, or a limited number of people to test and debug it (fix it’s errors).
After testing and debugging. SOME of the programmers who worked on it keeps a copy of it. And before the company brings out the original software they share the one which was in Dev mode with others. That is when the software leaks.
But that doesn’t mean they’ve committed a crime. Why are we saying that? The reason is, there is something in software called “beta version”.
A beta version is a version of a piece of software that is made available for testing, typically by a limited number of users outside the company that is developing it, before its general release.
Some companies prefer to bring out the “under development mode software” for people to test. If you are not a developer, you may not even be able to use it. So, it is not bad to bring out a software before its general release. However, some companies don’t want everyone to get the Dev or Beta Versions before its original release. This happens when the Software is commercial (that is, you need to buy it before you can use).
So in short a software leak means, the Dev or Beta Version of a Commercial Software has been release to the public.
An important information from the software has been sold out.

This happens when a sensitive or confidential information from a Commercial or non-commercial software that hasn’t been announced or released has been sold or released to the public. This information includes the software’s source code, personal information in the software, etc.
Read more here <https://en.wikipedia.org/wiki/Internet_leak#Source_code_leaks>
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To summarize everything, software leak isn’t always a bad thing. But sometimes, other Bad Developers (Hackers) plant malware in those software for you to download.
We will provide an article for you to know how you can prevent yourself from being hacked with under development softwares. While waiting, You can read about how to remove write protection from Pen Drives